Okay possibly a stupid question... but, does anyone actually use this to put your baby to sleep in?

I have just set one up at my MILs house for my baby, and discover that:

a) the "mattress" and i use this term loosely, because its essentially a plank of wood with a centimetre of padding - is extremely hard!

and

b) It says inside not to leave your baby unattended.... (well pointless if my idea was to put him asleep in another room)

So i'm wondering if its just supposed to be a playpen of some sort? It also says not to add padding or another mattress, which i was going to do so i could let him sleep in it. Am now wondering if i should just buy another normal cot as he'd be using it at least once a week.